/*
 *
 * Copyright (c) 2005 The Exceoon Software Foundation.  All rights
 * reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 *
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in
 *    the documentation and/or other materials provided with the
 *    distribution.
 *
 * 3. The end-user documentation included with the redistribution,
 *    if any, must include the following acknowledgment:
 *       "This product includes software developed by the
 *        Exceoon Software Foundation (http://www.exceoon.com/)."
 *    Alternately, this acknowledgment may appear in the software itself,
 *    if and wherever such third-party acknowledgments normally appear.
 *
 * 4. Products derived from this software may not be called " Exceoon ",
 *    nor may " Exceoon " appear in their name, without prior written
 *    permission of the Exceoon Software Foundation.
 *
 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
 * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
 * DISCLAIMED.  IN NO EVENT SHALL THE APACHE SOFTWARE FOUNDATION OR
 * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
 * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
 * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
 * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 * ====================================================================
 *
 * This software consists of voluntary contributions made by many
 * Exceoon Software Corporation and was originally based on software
 * Exceoon copyright (c) 2005, International
 * Business Machines, Inc., http://www.Exceoon.com.  For more
 * information on the Exceoon Software Foundation, please see
 * <http://www.Exceoon.com/>.
 */

package com.exceoon.equals.formula.support;

import java.util.List;

import fr.expression4j.basic.ExpressionElement;
import fr.expression4j.basic.MathematicalElement;
import fr.expression4j.basic.OperatorManager;
import fr.expression4j.basic.ParseInfo;
import fr.expression4j.core.Catalog;
import fr.expression4j.core.ExpressionModel;
import fr.expression4j.core.Parameters;
import fr.expression4j.core.exception.EvalException;
import fr.expression4j.core.exception.ParsingException;
import fr.expression4j.core.impl.TreeElement;
import fr.expression4j.util.ExpressionElementUtil;

/**
 * Author	David.Liu 
 * Mail		david.liu@exceoon.com
 * copyright	Exceoon corporation
 */

public class FieldExpressionElement implements ExpressionElement
{

	public FieldExpressionElement()
	{
		super();
	}

	/*
	 * (non-Javadoc)
	 * 
	 * @see
	 * fr.expression4j.basic.ExpressionElement#parseElement(java.lang.String,
	 * fr.expression4j.basic.ParseInfo)
	 */
	@SuppressWarnings("unchecked")
	public boolean parseElement(String expression,
	        ExpressionModel expressionModel, ParseInfo parseInfo,
	        Catalog catalog, List functionParameters, int priorityOperatorLevel)
	        throws ParsingException
	{
		int startPos = parseInfo.getEndPos();
		int currentPos = parseInfo.getEndPos();

		if (ExpressionElementUtil.checkPosition(expression, currentPos)
		        && "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz"
		                .indexOf(expression.charAt(currentPos)) != -1)
		{
			currentPos++;
			while (ExpressionElementUtil.checkPosition(expression, currentPos)
			        && "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789_"
			                .indexOf(expression.charAt(currentPos)) != -1)
			{
				currentPos++;
			}
		}

		if (currentPos == startPos)
		{
			return false;
		}

		String constantOrVariableName = expression.substring(startPos,
		        currentPos);

		// check if it is a constant
		if (DataSource.isDefined(constantOrVariableName))
		{
			// it is a constant
			TreeElement result = new TreeElement(
			        TreeElement.TREE_ELEMENT_TYPE_EXPRESSION_ELEMENT, null,
			        null, null, getName(), constantOrVariableName, null);
			parseInfo.setTreeElement(result);
			parseInfo.setEndPos(currentPos);
			return true;
		} else
		{
			return false;
		}
	}

	/*
	 * (non-Javadoc)
	 * 
	 * @see fr.expression4j.basic.ExpressionElement#getName()
	 */
	public String getName()
	{
		return "FieldExpressionElement";
	}

	public MathematicalElement evaluate(TreeElement element, Catalog catalog,
	        OperatorManager operatorManager, Parameters parameters,
	        ExpressionModel model) throws EvalException
	{

		String constantOrVariableName = element.getStringElement();

		return DataSource.getObjectValues(constantOrVariableName, 100);

	}

	public String toString(TreeElement element, ExpressionModel expressionModel)
	{
		return element.getStringElement();
	}

}
